To effectively assist in the treatment of patients, healthcare professionals (nurses, medical assistants, paramedics, etc.) are responsible for performing accurate calculations and measurements of medications prescribed by medical physicians. Generally, the various units of doctor-prescribed medication are different from the units of medication defined by a pharmacy. Clinical staff must therefore appropriately convert and precisely calculate a medication dosage in accordance with both the physician's order and pharmaceutical standards. Due to the stressful environment associated with emergency situations as well as the long and difficult hours typically required in the healthcare profession, verification of manual dosage calculations has been very difficult or non-existent even though such verification has long been desirable.
Without proper verification, miscalculations in dosages will occur. According to a November 1999 report from the Institute of Medicine, clinical mistakes in calculating medical dosage, among other factors, kill an estimated 44,000 to 98,000 hospitalized Americans each year. Another article reports that “calculation errors in prescribing are a well-recognized problem, in which errors in decimal point placement, mathematical calculation, or expression of dosage regimen account for 59.5% of dosage errors. Conclusions: The use of equations to determine medication dosages presents considerable risk to patients for errant dosing and subsequent adverse events or therapeutic failure. Errors may occur in any component of a dosage equation.” (Arch. Pediatr. Adolesc. Med. 1998 Apr.: 152 (4): 340–4, “Errors in the Use of Medication Dosage Equations.”)
Further errors in medical dosage arise from the conversion of dosage units prescribed by the physician into pharmaceutical standard dosages. In cases where the prescriptive drugs are provided in solution at a specific concentration per volume of fluid, or a specific mass per tablet, a clinician must compute the correct total dosage to be administered to a patient. For example, most common problems in administering medications in healthcare are associated with conversions of drug dosage units.
Other errors in medicinal calculations occur with the administration of medication by intravenous fluids. Current methods for assuring accuracy in administering medications via intravenous fluids include programmable pumps similar to those pump's disclosed in U.S. Pat. Nos. 5,772,635; 5,681,285; 4,898,578; and 4,714,462. However, such programmable pumps are costly, expensive to maintain, and not always readily available. Therefore, manual hand calculations for administering medications using intravenous fluid are very often required. In such cases, intravenous fluids are administered by manually setting a drip chamber to allow a certain number of drops per minute to enter the intravenous tubing from the IV bag and to flow into the patient's vein. When the nurse or technician manually sets the flow rate by setting drip chambers, they have to carry out hand calculations to determine the appropriate number of drops per minute for the fluid to flow in accordance with the correct total dose for the patient. Since there are no quick and easy-to-use devices available to help perform such dosage conversions, hand calculations of drug dosages or flow rates are often performed.
Miscalculation of medication dosages can arise from incorrect manual calculations by the health care professional or student due to errors in calculation setups or in incorrect data entry. In particular, beginning nursing students and/or medical assistants encounter problems as they learn to correctly set up equations. Errors often arise from simple arithmetic mistakes in addition, subtraction, multiplication, and division. It has been noted that “medication error is a preventable event that may cause or lead to inappropriate medication use or patient harm while the medication is in the control of the health care professional, patient, or consumer. Such events may be related to professional practice; health care products, procedures, and systems including prescribing, order communication; product labeling, packaging and nomenclature; compounding, dispensing, distribution; administration; education; monitoring; and use.” (About Medication Errors, National Coordinating Council for Medication Error Reporting and Prevention, 1998–1999.)
Several complex, hand-held apparatuses have been developed to assist healthcare professionals in evaluating medical information. For example, U.S. Pat. No. 6,167,412 teaches a hand-held calculator that performs specific clinical functions including storage/recall for numbers, phone directory, degree/radian, time, date alarms, and hemodynamics and cardiac functions; U.S. Pat. No. 5,630,664 discloses a hand-held apparatus for calculating and converting ECG waveforms and other graphically displayed data; and U.S. Pat. No. 5,915,971 teaches a hand-held device for teaching healthcare professionals how to determine a calculated drug dosage.
Further apparatuses directed to performing or recording medical information require a means for communicating with a host computer or server. For example, U.S. Pat. No. 5,781,442 discloses a system and method for patient care management; U.S. Pat. No. 5,272,318 teaches a system for ensuring proper treatment is being administered to the correct patient; U.S. Pat. No. 5,261,702 teaches a system for monitoring daily administration of medication to a patient; U.S. Pat. Nos. 5,088,981 and 4,810,243 disclose various programmable systems for customized delivery of medication to a patient; and U.S. Pat. No. 4,807,170 discloses a computer system for calculating drug administration rates for IV systems.
Although these various devices are beneficial in the health care profession, each is complex to operate and requires in-depth instruction on use. In addition, such devices are often expensive to purchase and to maintain. More importantly, these devices may actually lead to further dosage miscalculations as a result of user inability to properly operate the device.
Therefore, a quick and simple method and device for calculating dosage rates would benefit patient treatment, as current methods for determining drug dosages or flow rates are either manually/mentally calculated or require in-depth understanding of complex devices. Implementing a quick and simple means for accurately converting and calculating prescription dosages would also relieve clinicians from the time-consuming task of performing tedious and repetitive calculations and reduce the potential life threatening errors generated by hand calculations.